Radiation Damage Effects in Insulators for Fusion Reactors: Microstructure Evolution in MgO-Al2O3 System Oxide Crystals

Abstract

Characteristic features of radiation damage in insulators for fusion reactors are that those materials are exposed to synergistic radiation damage of elastic displacements and electric excitation with the presence of an electric field. This paper describes the nucleation-and-growth of radiation-induced defects and their stability in oxide ceramics, such as magnesium-aluminate spinel (MgAl2O4) and alpha-alumina (α-Al2O3). Microstructure evolution in these oxides is shown through transmission electron microscopy for the formation process of dislocation loops under synergistic irradiation with displacements and ionizing radiation, the stability of dislocation loops, and the nucleation-and-growth process of loops with an applied electric field.